The upgrade was straight from a Sell rating.
And i was using TipRanks Add On when reading this, so here are a few more statistics:
The analyst behind the upgrade is Sameet Sinha which is ranked high..
His average return on recommendations measured is +13% (above S&P500) while his success rate is 50% only - still he is definitely someone to listen too.
Sentiment: Strong Buy
I don't follow the stock closely or have a position. But who the hell goes from sell to buy and $7 to $18? Whatever. It sounds like a pump to me.